1. Field of Invention
The inventive subject matter relates to methods for programming a neural prosthesis, more particularly to methods for programming a hearing prosthesis, and most particularly to methods for fitting a speech processor and implantable cochlear stimulator by programming the speech processor.
2. Background
Hundreds of disorders affect the nervous system. Some, like stroke, the epilepsies, and Alzheimer's disease and other effects of aging, affect millions of Americans. Many neurological disorders produce a loss of function in motor and/or sensory nerve pathways, resulting in a variety of disabilities in humans. An important part of the effort to restore function in neurologically disabled individuals is the use of neural prosthetics. Neural prostheses are electronic and mechanical devices that connect with the nervous system to restore lost function. Such devices generally include electrodes that interface with biological tissue, a power and telemetry receiver, control electronics, and a biocompatible package for the implanted electronics.
Present devices afford some restoration of function in relation to their biological counterparts, but research is ongoing to improve the function of these devices. The Neural Prosthesis Program at the National Institute of Neurological Disorders and Stroke of the National Institutes of Health supports the development of implants for the purpose of forming in-going and out-going connections with the nervous system, which are needed for the development of neural prostheses for individuals with sensory and motor disabilities. Prosthetic devices for all the five major senses—hearing, sight, touch, taste, and smell—are under development. With the ongoing development of more sophisticated and sensitive devices, the need for the effective programming or fitting of a device to an individual is expected to increase. A goal of the inventive subject matter is to contribute to the overall process of reducing the burden of neurological disorders by providing methods for the improved, user-directed programming or fitting of a neural prosthesis, particularly a hearing prosthesis, and most particularly to a cochlear implant or other implantable hearing prosthesis having a speech processor.
An exemplary class of sensorineural prosthetic devices are the hearing prostheses. Types of hearing prostheses include simple sound amplification devices such as the traditional hearing aid; more sophisticated sound amplification devices which are adjustable to the specific deficiencies in a user's hearing profile; and implantable devices such as cochlear implants and cortical implants, which bypass the organic hearing mechanism and directly stimulate the sensory nerves and/or brain centers of hearing, to replicate the ability to perceive sound. Other sensorineural prosthetics currently under development include vision prostheses, tactile sensation prostheses, olfactory prostheses, and gustatory prostheses.
Cochlear prostheses produce sensations of sound in deaf patients by direct electrical stimulation of the auditory nerve. In modern, multichannel cochlear prostheses, several different sites are stimulated at various distances along the cochlea to evoke the different pitches of sound perception that are normally encoded by nerve activity originating from the respective sites. The patterns of electrical stimulation are derived from acoustic signals picked up by a microphone and transformed by a speech processor that is programmed to meet the particular requirements of each patient.
Several different schemes for processing the acoustic signal and transforming it into electrical stimuli have been developed; see U.S. Pat. No. 3,751,605 (Michelson); U.S. Pat. No. 4,400,590 (Michelson); U.S. Pat. No. 4,267,410 (Forster et al.); U.S. Pat. No. 4,284,856 (Hochmair et al.); U.S. Pat. No. 4,408,608 (Daly et al.); U.S. Pat. No. 4,428,377 (Zollner et al.); and U.S. Pat. No. 4,532,930 (Crosby et al.). All such stimulators generate electrical stimulation pulses that may be selectively applied to the cochlea of a patient through an appropriate electrode or electrode array. Thus, U.S. Pat. Nos. 4,284,856 and 4,357,497 disclose a sound processor including multiple channel signal transmission to a subcutaneously implanted receiver for selectively stimulating the cochlea through electrodes in an implanted prosthesis.
The totally deaf or severely hearing impaired user of such implanted devices presents a special difficulty in fitting a speech processor. The middle or inner ear may be totally non-responsive to sound waves, but the auditory nerve generally can be electrically stimulated to transmit signals to the brain. Thus, in U.S. Pat. No. 4,284,856 the necessity of isoloudness frequency adjustment and dynamic range compression for the wearer of a cochlear prostheses have been disclosed. Establishing proper sound response characteristics of the auditory nerve in such patients is more critical and difficult than is the auditory response of a less severely impaired person. In the latter case, it is conventional to merely establish frequency response of the hearing device which matches the patient's dynamic range, based on an audiogram or other testing.
Thus, one of the more perplexing problems facing users of Cochlear implant systems, and the clinicians and physicians who implant and adjust such systems, is properly setting the stimulation parameters used by these systems. That is, each Cochlear implant system must be adjusted to fit an individual patient, so that sounds are properly perceived by that patient, and so that sounds are not painfully too loud, nor undetectably too soft, nor otherwise unintelligible by the patient.
As the art of cochlear stimulation has advanced, both the implanted portion of the cochlear stimulation system, and the externally wearable speech processor have become increasingly complicated and sophisticated. The amount of control and discretion exercisable by an audiologist in selecting the modes and methods of operation of the cochlear stimulation system have increased dramatically. It is no longer possible to fully control and customize the operation of the cochlear stimulation system through the use of, for example, switches located on the speech processor. As a result, it has become necessary to utilize an implantable cochlear stimulator fitting system to establish the operating modes and methods of the cochlear stimulation system and then to download such programming into the speech processor.
Currently, cochlear implants are fit within a clinical fitting environment where a clinician controls software to produce settings that, in turn, control the device. A clinician then tests the patient in an artificial listening environment with subjective materials, often highly subjective, and often with differing presentation levels, tester voices, etc.
Properly programming an implanted device is especially difficult because heretofore much of what is deemed a proper setting has been a determination made by the clinician, based on feedback from the patient. For example, U.S. Pat. No. 5,626,629 provides a clinician with various adjustment tools, including the use of a personal computer having a special software program loaded therein, that help the clinician set and adjust numerous stimulation parameters. However, due to the age, disability, or other limitations of the patient, often the patient is ineffective at accurately communicating what he or she senses or “hears” through the implant system to the attending medical personnel.
Others have attempted to overcome this lack of effective patient/clinician communication by removing patient feedback from the process. U.S. Pat. No. 6,157,861 discloses an implantable cochlear stimulator (ICS) and a method for fitting the ICS to a particular patient using objective feedback rather than subjective feedback. Such methods commonly rely upon measurements of the stapedius reflex response and the middle ear reflex to objectively measure physiological response to sound.
However, reliance on technology and/or objective measurements often does not provide a patient with a device fully optimized for helping the patient hear common sounds, such as voices, in real-world environments. Currently available systems for programming or fitting of cochlear stimulation systems, while providing a degree of flexibility in the programming of the modes and methods of operation of the cochlear stimulation system based solely or in part of objective measurements taken from the patient, lack the ability to fully integrate subjective patient observations as to the effectiveness of the hearing prosthesis.
Thus, there is a need in the neural stimulation art for techniques, methods, and systems for more accurately fitting a neural prosthesis to the individual patient. The complex biophysical phenomena associated with the electrical excitation of neurons and psychophysical phenomena regarding the interpretation of neural activity by the nervous system suggest that the quality and intelligibility of neural prostheses may be improved in a given patient by more specific manipulations of the electrical stimulus tailored to that patient.
The need for such a system becomes increasingly important with a decease in the age of the patient into which the neural stimulator, such as an implantable cochlear stimulator, is implanted. This is because very young patients, for example two year olds, are unable to provide adequate subjective feedback to the clinician programming the device to accurately fit the neural stimulation system optimally for the patient. Further, currently available programming units do not provide a level of feedback to the audiologist that enables the audiologist to independently evaluate the stimulation being applied to the patient, and thereby optimize such stimulation. Thus, what is needed is an improved apparatus and method for programming a speech processor of a neural stimulation system that provides for the efficient and effective utilization of subjective patient responses in the setting of the modes and methods of operation of the cochlear stimulation system.
Accordingly, an object of the invention is an improved method for fitting a neural prosthesis to a sensorineural-impaired person. Another object of the invention is an improved method for fitting a hearing prosthesis to a hearing impaired person. A further object of the invention is an improved method for fitting a sound processor driving a subcutaneously implanted receiver and prosthetic electrical structure to a severely hearing impaired person. A further object of the invention is an improved method for checking the fitting of a neural prosthesis to the needs of a user.
The inventive subject matter provides improved techniques for programming a neural prosthesis, more particularly a hearing prosthesis, and most particularly for programming an implanted hearing prosthesis such as a Cochlear implant system. The inventive subject matter allows the user of a neural prosthetic device to interface with fitting software directly without the intervention of a clinician. The process includes a video-game based graphical user interface, which is particularly effective with children. The inventive subject matter also includes software having a verification portion that tests a user's abilities with various settings to help the user maximize his or her abilities. The method is particularly advantageous with totally deaf and severely hearing impaired individuals, but the process has applicability to other hearing impaired persons requiring a hearing prosthesis and to other sensorineural-impaired persons requiring a neural prosthesis.
The inventive subject matter solves a number of problems. First, it removes the clinician from the process of relaying a user's perceptual information to the software. Second, with the use of an optional single presentation system in which electrical signals are directly input into the prosthesis, it reduces verification testing variability by eliminating the inherent errors, noise, and other interference which may be found in ambient testing room environments. Third, it eliminates or substantially reduces the clinician's time commitment to device fitting. Fourth, processor settings are optionally set by the user at home, eliminating the need for a clinic visit and associated travel by the user and/or the user's family members.